Extrusion

ABSTRACT

Extrusion apparatus comprising a wheel having a circumferential groove around its outer edge. A fixed shoe member bearing against the edge of the wheel has a die member projecting into the circumferential groove. Material to be extruded, such as a metal rod, is fed into the circumferential groove below the shoe member. The wheel is rotated relative to the shoe member so that the material is carried along the circumferential groove by frictional drag towards the die member and is extruded through an orifice in the die member. The shoe member has a portion projecting into the groove in the wheel and extending substantially from the material feed end to the abutment. The projecting portion is as close a fit as possible in the groove and serves to reduce the accumulation of flash between the wheel and the shoe member.

llite 1.

Green Mar. 25, 1975 EXTRUSION Primary Examiner-Richard J. Herbst Assistant Examiner-Robert M. Ro ers t 1 10 k G x g [75] or g Lytham Sam Annes Attorney, Agent, or Firm-Larson, Taylor & Hinds [73] Assignee: United Kingdom Atomic Energy Authority, London, England Filed: Aug. 14, 1973 Appl. No.: 388,163

Foreign Application Priority Data Sept. 5, 1972 United Kingdom 41133/72 References Cited UNITED STATES PATENTS 7/1956 Bicher 10/1973 Green [57] ABSTRACT Extrusion apparatus comprising a wheel having a circumferential groove around its outer edge. A fixed shoe member bearing against the edge of the wheel has a die member projecting into the circumferential groove. Material to be extruded, such as a metal rod, is fed into the circumferential groove below the shoe member. The wheel is rotated relative to the shoe member so that the material is carried along the circumferential groove by frictional drag towards the die member and is extruded through an orifice in the die member. The shoe member has a portion projecting into the groove in the wheel and extending substantially from the material feed end to the abutment. The projecting portion is as close a fit as possible in the groove and serves to reduce the accumulation of flash between the wheel and the shoe member.

4 Claims, 2 Drawing Figures 1 EXTRUSION BACKGROUND OF THE INVENTION The present invention relates to the forming of materials by extrusion.

US. Pat. Application Ser. No. 228,673, now US. Pat. No. 3,765,216, issued Oct. 16, 1973, which has been assigned to the present Assignee discloses and claims an extrusion apparatus which comprises first and second members defining an elongate passageway therebetween, said first and second members being movable one relative to the other in the direction of the length of the passageway, an abutment member fixed relative to the second member projecting into and blocking the passageway, means defining at least one die orifice leading from the passageway adjacent the abutment member, said orifice extending from said passageway to a point outside said apparatus whereby material fed to said apparatus is extruded therethrough, means for continuously feeding material to be extruded from a position outside said apparatus into said passageway at a point spaced from the abutment member,

the amount of the surface area of the passageway defined by the first member which is movable towards the abutment member being greater than the amount of the surface area of the passageway defined by the second member, whereby material fed into the passageway is moved by frictional drag with the surfaces of the passageway in the first member towards the abutment member and is thereby extruded through the die orifice.

The passageway can be formed by an endless groove in the first member with the second member being in the form of a shoe covering a part of the length of the groove. The shoe is positioned as close as possible to the first member and over the groove in the first member.

A material such as a metal to be extruded is drawn through the passageway by frictional drag with the surfaces of the passageway in the first member towards the abutment member. The resulting pressure build-up in the material can cause a portion of the material, hereinafter termed flash, to be extruded through the clearance between the first and second members. The flash tends to displace the first and second members apart and consequently as extrusion proceeds more and more flash tends to be extruded between the opposing portions of the first and second members.

The present invention seeks to provide a simple, inexpensive modification whereby to prevent the development of an unstable situation arising from the possible displacement of the second member away from the first member as mentioned above.

SUMMARY OF THE INVENTION According to the present invention the above mentioned second member has a portion projecting into the groove in the first member and having a width substantially equal to the width of the groove in the first member.

In this case any clearance for flash will exist between the side walls of the groove in the first member and the opposing side walls of the portion of the second member projecting into the groove. This clearance is across the direction in which flash tends to flow and is therefore unaffected by pressure within the passageway between the first and second members. This clearance will remain substantially constant during operation of the apparatus and even if the second member is deflected away from the first member, provided that the portion remains within the groove, the clearance for flash will remain unaffected and substantially constant.

Whilst the second member can be formed with an integral portion projecting into the groove in the first member, conveniently, a removable insert portion is employed which is accommodated in a corresponding groove in the second member. The abutment member for blocking the end of the passageway between the first and second members can be integral with the removable insert portion. At least one die orifice is provided in the removable insert portion in or adjacent the abutment, the die orifice or orifices communicating with an associated outlet passage or passages for extruded material in the second member. Further, means i can be provided in the second member for adjusting the position of the removable insert relative to the first 'member. The portion projecting into the groove in the first member can be formed from a material which is .resistant to wear, such as hard steel used in the manufacture of tools. A plurality of removable insert portions having different forms and arrangements of die orifices can be provided for use interchangeably with a common shoe member. I

DESCRIPTION OF THE DRAWINGS FIG. 2 is an enlarged section along the line lI in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The extrusion apparatus of FIG. 1 comprises a first member in the form of a wheel I rotatably mounted on a shaft 2. The wheel is formed with a continuous peripheral groove 3 of rectangular cross-section. A sec ond member 4 in the form ofa shoe fits about a portion of the periphery of the wheel. The face of the shoe 4 facing the wheel 1 is also formed with a groove 5 which receives a removable insert member 6 terminating at one end in an abutment 7. The insert member projects into the groove 3 in the wheel 1 with the abutment member substantially blocking the groove and hence the passage formed between the wheel 1 and the shoe 4. Means, not shown, can be provided for releasably securing the insert member 6 in the groove 3 and for radially adjusting the position of the insert member within the groove 3. A die orifice 8 is formed through the abutment member.

In use, material 9 to be extruded is fed into the passageway formed between the wheel 1 and the stationary shoe 4. The wheel 1 is rotated in a clockwise direction in FIG. 1 to draw the material beneath the shoe 4 and through the die orifice.

As shown in FIG. 2 the insert member projects into the groove in the wheel 1 and is dimensioned to substantially close the groove in the wheel, preferably with fine clearance rather than rubbing engagement. This fine clearance is denoted by the reference 10 in FIG. 2.

As extrusion proceeds some of the material may escape as flash through the clearances 10. However the flash cannot alter the clearances which will remain constant, provided the insert member projects into the groove, even if the shoe is caused to move away from the rim of the wheel 1. A stable situation is achieved.

The invention is not restricted to the illustrated embodiment. Thus the insert member can be formed integral with the shoe. Further a plurality of die orifices can be associated with the abutment and more than one shoe member can be associated with the groove in the wheel.

Finally, the groove wheel 1 can be replaced with an elongate endless grooved member. Such a member could be advantageous when it is required to extrude material from lengths of stock which are difficult to bend or to adopt into an arcuate configuration as is the case when the grooved member is a wheel.

I claim:

1. An extrusion apparatus comprising first and second members defining an elongate passageway therebetween, said first and second members being movable one relative to the other in the direction of the length of the passageway, an abutment member fixed relative to the second member projecting into and blocking the passageway, means defining at least one die orifice leading from the passageway adjacent the abutment member, said orifice extending from said passageway to a point outside said apparatus whereby material fed to said apparatus is extruded therethrough, the amount of the surface area of the passageway defined by the first member which is movable towards the abutment member being greater than the amount of the surface area of the passageway defined by the second member, whereby material fed into the passageway is moved by frictional drag with the surface of the passageway in the first member towards the abutment member and is thereby extruded through the die orifice, and in which said second member is provided with a further portion projecting into and extending over a length of the passageway in front of said abutment member and having a width substantially equal to the width of the passageway and being of lesser depth than the abutment member.

2. An extrusion apparatus according to claim 1 in which said portion projecting into the passageway is removable.

3. An extrusion apparatus according to claim 1 in which said portion is integral with the abutment member and is mounted in a groove in the surface ofthe second member overlying the first member.

4. An extrusion apparatus according to claim 1 in which the first member comprises a wheel member having an endless peripheral groove. 

1. An extrusion apparatus comprising first and second members defining an elongate passageway therebetween, said first and second members being movable one relative to the other in the direction of the length of the passageway, an abutment member fixed relative to the second member projecting into and blocking the passageway, means defining at least one die orifice leading from the passageway adjacent the abutment member, said orifice extending from said passageway to a point outside said apparatus whereby material fed to said apparatus is extruded therethrough, the amount of the surface area of the passageway defined by the first member which is movable towards the abutment member being greater than the amount of the surface area of the passageway defined by the second member, whereby material fed into the passageway is moved by frictional drag with the surface of the passageway in the first member towards the abutment member and is thereby extruded through the die orifice, and in which said second member is provided with a further portion projecting into and extending over a length of the passageway in front of said abutment member and having a width substantially equal to the width of the passageway and being of lesser depth than the abutment member.
 2. An extrusion apparatus according to claim 1 in which said portion projecting into the passageway is removable.
 3. An extrusion apparatus according to claim 1 in which said portion is integral with the abutment member and is mounted in a groove in the surface of the second member overlying the first member.
 4. An extrusion apparatus according to claim 1 in which the first member comprises a wheel member having an endless peripheral groove. 